Income Tax (Tax Effects of Temporary Differences that Give Rise to Significant Portions of the Deferred Income Tax Asset and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Deferred Tax Assets, Net [Abstract]
Deferred Tax Assets, Tax Deferred Expense, Reserves and Accruals	$ 116,106	$ 118,389
Deferred Tax Assets Reinsurance Transactions	63,543	64,445
Deferred Tax Assets Cash And Invested Assets	5,931	0
Deferred Tax Assets Investment Income	0	56,176
Deferred Tax Assets Deferred Acquisition Costs Capitalized For Tax	131,714	92,832
Deferred Tax Assets, Operating Loss Carryforwards	524,501	170,965
Deferred Tax Assets Deferred Acquisition Costs Capitalized For Financial Reporting	77,888	26,365
Deferred Tax Assets, Gross	919,683	529,172
Deferred Tax Assets, Valuation Allowance	(127,132)	(112,005)
Deferred Tax Assets, Net	792,551	417,167
Deferred Tax Liabilities [Abstract]
Deferred Tax Liabilities, Deferred Expense, Deferred Policy Acquisition Cost	1,011,753	961,170
Deferred Tax Liabilities Reinsurance Transactions	1,509,211	1,044,097
Deferred Tax Liabilities Cash And Invested Assets	336,870	667,601
Deferred Tax Liabilities Investment Income	14,654	8,187
Deferred Tax Liabilities, Unrealized Currency Transaction Gains	81,492	64,115
Deferred Tax Liabilities, Prepaid Expenses	1,014	0
Deferred Tax Liabilities	2,954,994	2,745,170
Net deferred income tax liabilities	2,162,443	2,328,003
Balance Sheet Presentation Of Deferred Tax Liabilities [Abstract]
Deferred Tax Assets, Other	55,885	37,814
Deferred income taxes	$ 2,218,328	$ 2,365,817